Recovery of cuprous sulfid from ores and the like.



R. F. BACON.

RECOVERY OF CUPROUS-SULHB FROM ORES AND THE LIKE.

APPLICATION FILED JAN- 24, I914. 1,151,235, Patented Aug. 24, 1915.

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MAL M Q m 7/ RAYMOND'F. BACON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 METALS RESEARCH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE.

Specification of Letters Patent.

Patented Aug. 24, 1915.

Application filed January 24, 1914. Serial No. 814,148.

To all whom it may concern:

Be it known that I, RAYMOND F. BACON, a citizen of the United States, residing at No. 4909 Forbes street, Pittsburgh, Allegheny county, State of Pennsylvania, have invented certain new and useful Improvements in Recovery of Cuprous Sulfid from Ores and the like; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention is based upon the discovery that when cupric sulfid is subjected, under suitable conditions, hereinafter specified, to the action of a hydrocarbon, the result of the reaction is to reduce the cupric sulfid to cuprous sulfid and to bring about a more or less complete union of the available hydrogen and sulfur to form hydrogen sulfid. The reaction taking place may be expressed generally by the following equation:

By employing a suitable excess of the hydrocarbon above the amount theoretically required, the resultant reduction to cuprous sulfid is practically quantitative, and any remaining undecomposed hydrocarbon may be recovered from the residue in any suitable manner, as, for instance, by distillation. 7

In the practice of the invention, it may be applied to the treatment of cupric sulfi'd derived either from some method of precipitation or which may be otherwise the product of some prior treatment, or which may occur, either alone, or admixed, or in combination with other ingredients, in an ore or other natural product or in an artificial product. In general, the process proceeds with special regularity and facility when the sulfid is a precipitate, probably on account of the condition of fine sub-division incident to precipitation, a condition which can be more or less approximated for natural products, furnace residues, and like materials containing cupric sulfid, by grinding or otherwise comminuting those products. As will hereinafter more fully appear, the hydrocarbon may be employed either in the solid, liquid, vaprous or gaseous condition, according to the particular exigencies of practice in any individual instance, and in particular, in accordance with their availab lity at the place of use and their market prlce, which, from commercial considerations, will, in many instances, determine the selection. 1

As illustrative of a convenient and economical method of putting the invention into practice, the following typical example may be given: The cupric sulfid may be charged into a suitable receiver, which may conveniently have the form and dimensions of an ordinary still, adapted to be heated, as, for instance, externally by direct firing, 1n theusual manner, or internally, and which is provided with the necessary means for admitting the sulfid charge, for supplying the hydrocarbon, and for the removal of the residual products of the treatment, either continuously or intermittently, and also with means for conducting off the hydrogen sulfid to the place of storage, condensation or use. If the cu pric sulfid charged contains a large quantity of moisture, as, for instance, in the case of a wet precipitate, the containing vessel should have a sufficient capacity, with respect to the charge, to take care of such foaming as is incident to the operation, or, any suitable means may be provided to suppress the foam or to prevent it from rising to too high a level above the upper surface of the charge; as, for instance, one or more air jets of high pressure may be directed upon the forming foam layer so as to break it up and release the imprisoned gases or vapors. So also, in order toprevent the condensation and return to the receptacle and charge of any water that has been driven off in the form of steam during the operation, the still or receptacle may be provided, in its interior and at the upper part thereof with a suitable insert through which the gases and vapors, including the hydrogen sulfid and steam may freely pass on their way to the exit pipe of the still and which, by reason of its location, is at such a temperature as to.

intercept and reconvert into steam any water which, condensing out of the escaping Vapors would tend to return to the charge.

When a solid or liquid hydrocarbon isemployed, it may either be mixed with the cupric sulfid and charged therewith into the receiving vessel or still, or, it may be ad mitted into the upper part of the vessel and permitted to drop upon the heated cupric of the charge, rather than to mix it therei with in the first instance, for the reason that by dropping the hydrocarbon upon the top of the charge, a quantitative reduction of the cupric sulfid to cuprous sulfid can be effected with a lesser supply of hydrocarbon, so as to reduce, and in some instances, to practically avoid the presence in the still at the termination of the operation of may large quantity of hydrocarbon to be eafter recovered by distillation. It will racially be desirable to employ an amount of hydrocarbon somewhat in excess of that theoretically required for the reaction. 7

It is also feasible to practice the invention by showering the cupric sulfid through an atmosphere of hydrocarbon vapor, say vaporized mineral oil; a convenient mode of thus showering the cupric sulfid through the mineral oil vapor may consist, for instance, of a rotatory horizontal or inclined cylinder, suitably heated, and provided with means for admitting the mineral oil vapor at one end thereof and allowing the volatile products of the reaction to take their exit at the other end, and being further provided with longitudinal ledges projecting radially inward and adapted to raise the cupric sulfid constituting the charge of the rotary cylinder and permitting it to drop, as will be readily. understood.

While, as hereinbefore indicated, the invention is not restricted to the use of any particular hydrocarbon, it is found feasible, convenient, and economical, in practice, to use what are known generally in the arts, as hydrocarbon residues, as, for instance, oils from which the lighter and more valuable distillates, such as gasolene, kerosene, and the lighter lubricating oils have been driven off. The hydrocarbon residues thus obtainable from the natural petroleums and other oils having a similar composition such as shale oils, are entirely adapted to the purpose, and may be specified as illustrative of those which may find ready acceptance for con unercial uses; so also, there are available for the uses of the invention naphthalene, and substances which, on heating, give considerable quantities of hydrocarbons, as, for

instance, asphalts and bitumens (natural and artifical) coal tar, water gas tar, wood resins,

more rapidly at higher temperatures, and

the process may be conducted to special advantage at temperatures representing the boiling point of the hydrocarbons usually emp1oyed,that is to say, temperatures rangingfrom 300 C. to 360 C. which Will represent approximately the usual commercial temperatures. Inasmuch as'the dissociation of the hydrogen sulfid begins at 'about 400 C. and becomes increasingly important at higher temperatures, it will be preferable to restrict the temperature ac cordingly, not permitting it to rise above say 500 C., so that there may be no material loss in the recovery of the hydrogen sulfid.

In the accompanying drawing is illustrated apparatus of a type adapted for the practice of the invention, although it will be understood that the illustration is merely representative of many arrangements which might be employed for the purpose.-

In the drawing, A indicates a lixiviation tank, of the usual kind, and B indicates a suitable number of towers communicating with the lixiviation tank and serving to receive the copper sulfate solution or copper chlorid solution therefrom. The towers B discharge upon a perforated grid 6 or the like, upon which the preci itate collects, and from which after being lter-pressed it may be ultimately removed in any suitable manner, to the car 0, or the 1ike,'which conveys it to the still or reaction vessel D.

Above the grid 5, the hydrogen sulfid (and whatever vapors are carried therein) is admitted into the towers, as, for instance, through annular perforated rings d communicating with the pipe 6.

E indicates a suitable receptacle for supplying the hydrocarbon to the reaction ves- I sel or still D, and the still is provided with a closable charging door 9, through which the precipitate may be conveniently admitted. The reaction vessel or still D may be located within a suitable furnace setting, so as to be heated externally, and, for conveniently emptying it, at the termination of the reaction period, it may be placed upon trunnions, so located that the solid products of the reaction consisting mainly of cuprous sulfid and of the carbon of the decomposed hydrocarbon may be discharged through the door g and into any suitable conveyor, as, forinstance, the car F. The copper may be recovered in a metallic state, in any suitable manner, as, for instance, by adding the mixture to the molten charge of a copper matte converter.

From below the grid 5, the spent leaching solution, from which the copper has been precipitated, as cupric sulfid, may be conducted by a pipe h to the sump H. As hereinbefore indicated, the precipitation of the cupric sulfid by the hydrogen sulfid has given to the solution a further quantity of free sulfuric acid, and, in the sump, or in the lixiviation tank itself, any additional quantity of acid may be supplied flexible or removable from so doing. From the pipe suitable to the particular ore under treatment. From the sump, the solution may be supplied to the lixiviation tank in any suitable manner, as for instance, by the pump 1.

Before returning the solution to the lixiviation tank, care must be taken to insure that the solution contains no important amount of hydrogen sulfid, inasmuch as any hydrogen'sulfid present therein would react with the dissolved sulfate or chlorid, to produce cupric sulfid, which, being insoluble in the leaching liquor, would be lost in the gangue. A. convenient and suitable method for avoiding this difficulty is to add to the. spent solution as it collects in the sump or afterward before its return to the lixiviation tank, a suflicient additional quantity of the unspent solution to precipitate whatever hydrogen sulfid is present.

' The high pressure air jets 21 for keeping down the foam in the reacting vessel or still D may be supplied with air in any suitable manner, as, for instance, from the pump J. Within the head a of the reaction vessel or still D is contained the insert is, hereinbefore referred to, which mayconveniently consist of a structure of aluminum or other suitable material adapted to be raised to a high heat by the escaping hydrogen sulfid and accompanying vapors on their Way to the exit pipe f of the vessel D, whereby, as hereinbefore explained, any Water which would tend to condense out of the vapors and to return to the charge is prevented f the hydrogen sulfid and accompanying vapors pass through the condensing worm f, and the water and other liquid condensates thus separated, are carried off from the collecting chamber h from time to time or continuously through the valved pipe m, while the hydrogen sulfid is pumped to the rings d by means of the pump N.

It will, of course, be understood that the several pipes serving the apparatus may be provided with suitable regulating or controlling cocks as shown, and with suitable connections and couplings to permit the tiltingof the vessel D,

I when desired.

What I claim is:

'1. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous state by means of a hydrocarbon atmosphere; substantially as described.

2. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous state by means of a hydrocarbon in a non-oxidizing atmosphere and at a relatively low temperature; substantially as described.

3. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous state by means of a hydrocarbon in a reducing atmosphere; substantially as described.

4. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous state by means of a hydrocarbon in a reducing atmosphere and at a relatively low temperature; substantially as described.

5. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous state by means of a hydrocarbon at the boiling point of said hydrocarbon; substantially as described.

6. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous state by means of a hydrocu-b -n at a temperature not above 500 0.; substantially as described.

7 The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous state by means of a hydrocarbon under conditions adapted to simultaneously reduce the I cupric sulfid practically quantitatively to cuprous sulfid and to effect a conversion of its sulfur into hydrogen sulfid; substantially as described.

8. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid in the form of a precipitate to reduce it to the cuprous state by means of a hydrocarbon under conditions adapted for the simultaneous reduction of sulfid and the formation of hydrogen sulfid; substantially as described.

9. The method of reducing cupric sulfid to cuprous sulfid, which comprises reacting upon the cupric sulfid to reduce it to the cuprous stateby means of a hydrocarbon. the hydrocarbon being present in excess of that required theoretically for the reduction,

and distilling ofl the residual hydrocarbon left in the charge at the termination of the reducing action; substantially as described.

In testimony whereof I aflix my signature, in presence oftwo witnesses.

RAYMOND F. BACON.

Witnesses: Y Y

R. P. SHIVELY, Joan C. PENNLE. 

